The third quarter for Oxford-based IPG Photonics was even tougher than expected, as the company's preliminary financial results came in less than originally expected.

As a result, shares of the laser manufacturer's stock began trading Friday down nearly 10 percent as the company's stock price hit a yearly low of below $140 a share.

It's a value loss of about $800 million to begin Friday.

The company's revenues for the quarter are expected to be about $355 million, but the company said in July it was hoping for revenues between $360 million and $390 million.

According to IPG's report Friday, foreign currency headwinds reduced revenue by about $5 million relative to exchange rates assumed in third-quarter guidance.

On a per share basis, earnings are now expected to top out at $1.87 versus the previously announced guidance of up to $2.05.

CEO Valentin Gapontsev cited the "global geopolitical and macroeconomic environment" as the leading factor behind the company's reduced earnings.

"These tariff and trade-related headwinds were the primary driver of weaker than expected performance for our business in China and Europe," he said, citing an ongoing trade dispute between the U.S. and some of its largest trade partners, including China.

Full-year revenue growth could be below the 7-percent to 9-percent range the company predicted during the summer.

The company lost about third of its value on July 31 when it announced its second quarter results, a value loss of about $3 billion.